[deliverable/linux.git] / drivers / gpu / drm / drm_context.c

/**
 * \file drm_context.c
 * IOCTLs for generic contexts
 *
 * \author Rickard E. (Rik) Faith <faith@valinux.com>
 * \author Gareth Hughes <gareth@valinux.com>
 */

/*
 * Created: Fri Nov 24 18:31:37 2000 by gareth@valinux.com
 *
 * Copyright 1999, 2000 Precision Insight, Inc., Cedar Park, Texas.
 * Copyright 2000 VA Linux Systems, Inc., Sunnyvale, California.
 * All Rights Reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice (including the next
 * paragraph) shall be included in all copies or substantial portions of the
 * Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * VA LINUX SYSTEMS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 * OTHER DEALINGS IN THE SOFTWARE.
 */

/*
 * ChangeLog:
 *  2001-11-16	Torsten Duwe <duwe@caldera.de>
 *		added context constructor/destructor hooks,
 *		needed by SiS driver's memory management.
 */

#include <drm/drmP.h>

/******************************************************************/
/** \name Context bitmap support */
/*@{*/

/**
 * Free a handle from the context bitmap.
 *
 * \param dev DRM device.
 * \param ctx_handle context handle.
 *
 * Clears the bit specified by \p ctx_handle in drm_device::ctx_bitmap and the entry
 * in drm_device::ctx_idr, while holding the drm_device::struct_mutex
 * lock.
 */
void drm_ctxbitmap_free(struct drm_device * dev, int ctx_handle)
{
	mutex_lock(&dev->struct_mutex);
	idr_remove(&dev->ctx_idr, ctx_handle);
	mutex_unlock(&dev->struct_mutex);
}

/**
 * Context bitmap allocation.
 *
 * \param dev DRM device.
 * \return (non-negative) context handle on success or a negative number on failure.
 *
 * Allocate a new idr from drm_device::ctx_idr while holding the
 * drm_device::struct_mutex lock.
 */
static int drm_ctxbitmap_next(struct drm_device * dev)
{
	int ret;

	mutex_lock(&dev->struct_mutex);
	ret = idr_alloc(&dev->ctx_idr, NULL, DRM_RESERVED_CONTEXTS, 0,
			GFP_KERNEL);
	mutex_unlock(&dev->struct_mutex);
	return ret;
}

/**
 * Context bitmap initialization.
 *
 * \param dev DRM device.
 *
 * Initialise the drm_device::ctx_idr
 */
int drm_ctxbitmap_init(struct drm_device * dev)
{
	idr_init(&dev->ctx_idr);
	return 0;
}

/**
 * Context bitmap cleanup.
 *
 * \param dev DRM device.
 *
 * Free all idr members using drm_ctx_sarea_free helper function
 * while holding the drm_device::struct_mutex lock.
 */
void drm_ctxbitmap_cleanup(struct drm_device * dev)
{
	mutex_lock(&dev->struct_mutex);
	idr_destroy(&dev->ctx_idr);
	mutex_unlock(&dev->struct_mutex);
}

/*@}*/

/******************************************************************/
/** \name Per Context SAREA Support */
/*@{*/

/**
 * Get per-context SAREA.
 *
 * \param inode device inode.
 * \param file_priv DRM file private.
 * \param cmd command.
 * \param arg user argument pointing to a drm_ctx_priv_map structure.
 * \return zero on success or a negative number on failure.
 *
 * Gets the map from drm_device::ctx_idr with the handle specified and
 * returns its handle.
 */
int drm_getsareactx(struct drm_device *dev, void *data,
		    struct drm_file *file_priv)
{
	struct drm_ctx_priv_map *request = data;
	struct drm_local_map *map;
	struct drm_map_list *_entry;

	mutex_lock(&dev->struct_mutex);

	map = idr_find(&dev->ctx_idr, request->ctx_id);
	if (!map) {
		mutex_unlock(&dev->struct_mutex);
		return -EINVAL;
	}

	request->handle = NULL;
	list_for_each_entry(_entry, &dev->maplist, head) {
		if (_entry->map == map) {
			request->handle =
			    (void *)(unsigned long)_entry->user_token;
			break;
		}
	}

	mutex_unlock(&dev->struct_mutex);

	if (request->handle == NULL)
		return -EINVAL;

	return 0;
}

/**
 * Set per-context SAREA.
 *
 * \param inode device inode.
 * \param file_priv DRM file private.
 * \param cmd command.
 * \param arg user argument pointing to a drm_ctx_priv_map structure.
 * \return zero on success or a negative number on failure.
 *
 * Searches the mapping specified in \p arg and update the entry in
 * drm_device::ctx_idr with it.
 */
int drm_setsareactx(struct drm_device *dev, void *data,
		    struct drm_file *file_priv)
{
	struct drm_ctx_priv_map *request = data;
	struct drm_local_map *map = NULL;
	struct drm_map_list *r_list = NULL;

	mutex_lock(&dev->struct_mutex);
	list_for_each_entry(r_list, &dev->maplist, head) {
		if (r_list->map
		    && r_list->user_token == (unsigned long) request->handle)
			goto found;
	}
      bad:
	mutex_unlock(&dev->struct_mutex);
	return -EINVAL;

      found:
	map = r_list->map;
	if (!map)
		goto bad;

	if (IS_ERR(idr_replace(&dev->ctx_idr, map, request->ctx_id)))
		goto bad;

	mutex_unlock(&dev->struct_mutex);

	return 0;
}

/*@}*/

/******************************************************************/
/** \name The actual DRM context handling routines */
/*@{*/

/**
 * Switch context.
 *
 * \param dev DRM device.
 * \param old old context handle.
 * \param new new context handle.
 * \return zero on success or a negative number on failure.
 *
 * Attempt to set drm_device::context_flag.
 */
static int drm_context_switch(struct drm_device * dev, int old, int new)
{
	if (test_and_set_bit(0, &dev->context_flag)) {
		DRM_ERROR("Reentering -- FIXME\n");
		return -EBUSY;
	}

	DRM_DEBUG("Context switch from %d to %d\n", old, new);

	if (new == dev->last_context) {
		clear_bit(0, &dev->context_flag);
		return 0;
	}

	return 0;
}

/**
 * Complete context switch.
 *
 * \param dev DRM device.
 * \param new new context handle.
 * \return zero on success or a negative number on failure.
 *
 * Updates drm_device::last_context and drm_device::last_switch. Verifies the
 * hardware lock is held, clears the drm_device::context_flag and wakes up
 * drm_device::context_wait.
 */
static int drm_context_switch_complete(struct drm_device *dev,
				       struct drm_file *file_priv, int new)
{
	dev->last_context = new;	/* PRE/POST: This is the _only_ writer. */

	if (!_DRM_LOCK_IS_HELD(file_priv->master->lock.hw_lock->lock)) {
		DRM_ERROR("Lock isn't held after context switch\n");
	}

	/* If a context switch is ever initiated
	   when the kernel holds the lock, release
	   that lock here. */
	clear_bit(0, &dev->context_flag);

	return 0;
}

/**
 * Reserve contexts.
 *
 * \param inode device inode.
 * \param file_priv DRM file private.
 * \param cmd command.
 * \param arg user argument pointing to a drm_ctx_res structure.
 * \return zero on success or a negative number on failure.
 */
int drm_resctx(struct drm_device *dev, void *data,
	       struct drm_file *file_priv)
{
	struct drm_ctx_res *res = data;
	struct drm_ctx ctx;
	int i;

	if (res->count >= DRM_RESERVED_CONTEXTS) {
		memset(&ctx, 0, sizeof(ctx));
		for (i = 0; i < DRM_RESERVED_CONTEXTS; i++) {
			ctx.handle = i;
			if (copy_to_user(&res->contexts[i], &ctx, sizeof(ctx)))
				return -EFAULT;
		}
	}
	res->count = DRM_RESERVED_CONTEXTS;

	return 0;
}

/**
 * Add context.
 *
 * \param inode device inode.
 * \param file_priv DRM file private.
 * \param cmd command.
 * \param arg user argument pointing to a drm_ctx structure.
 * \return zero on success or a negative number on failure.
 *
 * Get a new handle for the context and copy to userspace.
 */
int drm_addctx(struct drm_device *dev, void *data,
	       struct drm_file *file_priv)
{
	struct drm_ctx_list *ctx_entry;
	struct drm_ctx *ctx = data;

	ctx->handle = drm_ctxbitmap_next(dev);
	if (ctx->handle == DRM_KERNEL_CONTEXT) {
		/* Skip kernel's context and get a new one. */
		ctx->handle = drm_ctxbitmap_next(dev);
	}
	DRM_DEBUG("%d\n", ctx->handle);
	if (ctx->handle == -1) {
		DRM_DEBUG("Not enough free contexts.\n");
		/* Should this return -EBUSY instead? */
		return -ENOMEM;
	}

	ctx_entry = kmalloc(sizeof(*ctx_entry), GFP_KERNEL);
	if (!ctx_entry) {
		DRM_DEBUG("out of memory\n");
		return -ENOMEM;
	}

	INIT_LIST_HEAD(&ctx_entry->head);
	ctx_entry->handle = ctx->handle;
	ctx_entry->tag = file_priv;

	mutex_lock(&dev->ctxlist_mutex);
	list_add(&ctx_entry->head, &dev->ctxlist);
	mutex_unlock(&dev->ctxlist_mutex);

	return 0;
}

/**
 * Get context.
 *
 * \param inode device inode.
 * \param file_priv DRM file private.
 * \param cmd command.
 * \param arg user argument pointing to a drm_ctx structure.
 * \return zero on success or a negative number on failure.
 */
int drm_getctx(struct drm_device *dev, void *data, struct drm_file *file_priv)
{
	struct drm_ctx *ctx = data;

	/* This is 0, because we don't handle any context flags */
	ctx->flags = 0;

	return 0;
}

/**
 * Switch context.
 *
 * \param inode device inode.
 * \param file_priv DRM file private.
 * \param cmd command.
 * \param arg user argument pointing to a drm_ctx structure.
 * \return zero on success or a negative number on failure.
 *
 * Calls context_switch().
 */
int drm_switchctx(struct drm_device *dev, void *data,
		  struct drm_file *file_priv)
{
	struct drm_ctx *ctx = data;

	DRM_DEBUG("%d\n", ctx->handle);
	return drm_context_switch(dev, dev->last_context, ctx->handle);
}

/**
 * New context.
 *
 * \param inode device inode.
 * \param file_priv DRM file private.
 * \param cmd command.
 * \param arg user argument pointing to a drm_ctx structure.
 * \return zero on success or a negative number on failure.
 *
 * Calls context_switch_complete().
 */
int drm_newctx(struct drm_device *dev, void *data,
	       struct drm_file *file_priv)
{
	struct drm_ctx *ctx = data;

	DRM_DEBUG("%d\n", ctx->handle);
	drm_context_switch_complete(dev, file_priv, ctx->handle);

	return 0;
}

/**
 * Remove context.
 *
 * \param inode device inode.
 * \param file_priv DRM file private.
 * \param cmd command.
 * \param arg user argument pointing to a drm_ctx structure.
 * \return zero on success or a negative number on failure.
 *
 * If not the special kernel context, calls ctxbitmap_free() to free the specified context.
 */
int drm_rmctx(struct drm_device *dev, void *data,
	      struct drm_file *file_priv)
{
	struct drm_ctx *ctx = data;

	DRM_DEBUG("%d\n", ctx->handle);
	if (ctx->handle != DRM_KERNEL_CONTEXT) {
		if (dev->driver->context_dtor)
			dev->driver->context_dtor(dev, ctx->handle);
		drm_ctxbitmap_free(dev, ctx->handle);
	}

	mutex_lock(&dev->ctxlist_mutex);
	if (!list_empty(&dev->ctxlist)) {
		struct drm_ctx_list *pos, *n;

		list_for_each_entry_safe(pos, n, &dev->ctxlist, head) {
			if (pos->handle == ctx->handle) {
				list_del(&pos->head);
				kfree(pos);
			}
		}
	}
	mutex_unlock(&dev->ctxlist_mutex);

	return 0;
}

/*@}*/
Commit	Line	Data
	1	/**
	2	* \file drm_context.c
	3	* IOCTLs for generic contexts
	4	*
	5	* \author Rickard E. (Rik) Faith <faith@valinux.com>
	6	* \author Gareth Hughes <gareth@valinux.com>
	7	*/
	8
	9	/*
	10	* Created: Fri Nov 24 18:31:37 2000 by gareth@valinux.com
	11	*
	12	* Copyright 1999, 2000 Precision Insight, Inc., Cedar Park, Texas.
	13	* Copyright 2000 VA Linux Systems, Inc., Sunnyvale, California.
	14	* All Rights Reserved.
	15	*
	16	* Permission is hereby granted, free of charge, to any person obtaining a
	17	* copy of this software and associated documentation files (the "Software"),
	18	* to deal in the Software without restriction, including without limitation
	19	* the rights to use, copy, modify, merge, publish, distribute, sublicense,
	20	* and/or sell copies of the Software, and to permit persons to whom the
	21	* Software is furnished to do so, subject to the following conditions:
	22	*
	23	* The above copyright notice and this permission notice (including the next
	24	* paragraph) shall be included in all copies or substantial portions of the
	25	* Software.
	26	*
	27	* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
	28	* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
	29	* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
	30	* VA LINUX SYSTEMS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
	31	* OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
	32	* ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
	33	* OTHER DEALINGS IN THE SOFTWARE.
	34	*/
	35
	36	/*
	37	* ChangeLog:
	38	* 2001-11-16 Torsten Duwe <duwe@caldera.de>
	39	* added context constructor/destructor hooks,
	40	* needed by SiS driver's memory management.
	41	*/
	42
	43	#include <drm/drmP.h>
	44
	45	/******************************************************************/
	46	/** \name Context bitmap support */
	47	/@{/
	48
	49	/**
	50	* Free a handle from the context bitmap.
	51	*
	52	* \param dev DRM device.
	53	* \param ctx_handle context handle.
	54	*
	55	* Clears the bit specified by \p ctx_handle in drm_device::ctx_bitmap and the entry
	56	* in drm_device::ctx_idr, while holding the drm_device::struct_mutex
	57	* lock.
	58	*/
	59	void drm_ctxbitmap_free(struct drm_device * dev, int ctx_handle)
	60	{
	61	mutex_lock(&dev->struct_mutex);
	62	idr_remove(&dev->ctx_idr, ctx_handle);
	63	mutex_unlock(&dev->struct_mutex);
	64	}
	65
	66	/**
	67	* Context bitmap allocation.
	68	*
	69	* \param dev DRM device.
	70	* \return (non-negative) context handle on success or a negative number on failure.
	71	*
	72	* Allocate a new idr from drm_device::ctx_idr while holding the
	73	* drm_device::struct_mutex lock.
	74	*/
	75	static int drm_ctxbitmap_next(struct drm_device * dev)
	76	{
	77	int ret;
	78
	79	mutex_lock(&dev->struct_mutex);
	80	ret = idr_alloc(&dev->ctx_idr, NULL, DRM_RESERVED_CONTEXTS, 0,
	81	GFP_KERNEL);
	82	mutex_unlock(&dev->struct_mutex);
	83	return ret;
	84	}
	85
	86	/**
	87	* Context bitmap initialization.
	88	*
	89	* \param dev DRM device.
	90	*
	91	* Initialise the drm_device::ctx_idr
	92	*/
	93	int drm_ctxbitmap_init(struct drm_device * dev)
	94	{
	95	idr_init(&dev->ctx_idr);
	96	return 0;
	97	}
	98
	99	/**
	100	* Context bitmap cleanup.
	101	*
	102	* \param dev DRM device.
	103	*
	104	* Free all idr members using drm_ctx_sarea_free helper function
	105	* while holding the drm_device::struct_mutex lock.
	106	*/
	107	void drm_ctxbitmap_cleanup(struct drm_device * dev)
	108	{
	109	mutex_lock(&dev->struct_mutex);
	110	idr_destroy(&dev->ctx_idr);
	111	mutex_unlock(&dev->struct_mutex);
	112	}
	113
	114	/@}/
	115
	116	/******************************************************************/
	117	/** \name Per Context SAREA Support */
	118	/@{/
	119
	120	/**
	121	* Get per-context SAREA.
	122	*
	123	* \param inode device inode.
	124	* \param file_priv DRM file private.
	125	* \param cmd command.
	126	* \param arg user argument pointing to a drm_ctx_priv_map structure.
	127	* \return zero on success or a negative number on failure.
	128	*
	129	* Gets the map from drm_device::ctx_idr with the handle specified and
	130	* returns its handle.
	131	*/
	132	int drm_getsareactx(struct drm_device dev, void data,
	133	struct drm_file *file_priv)
	134	{
	135	struct drm_ctx_priv_map *request = data;
	136	struct drm_local_map *map;
	137	struct drm_map_list *_entry;
	138
	139	mutex_lock(&dev->struct_mutex);
	140
	141	map = idr_find(&dev->ctx_idr, request->ctx_id);
	142	if (!map) {
	143	mutex_unlock(&dev->struct_mutex);
	144	return -EINVAL;
	145	}
	146
	147	request->handle = NULL;
	148	list_for_each_entry(_entry, &dev->maplist, head) {
	149	if (_entry->map == map) {
	150	request->handle =
	151	(void *)(unsigned long)_entry->user_token;
	152	break;
	153	}
	154	}
	155
	156	mutex_unlock(&dev->struct_mutex);
	157
	158	if (request->handle == NULL)
	159	return -EINVAL;
	160
	161	return 0;
	162	}
	163
	164	/**
	165	* Set per-context SAREA.
	166	*
	167	* \param inode device inode.
	168	* \param file_priv DRM file private.
	169	* \param cmd command.
	170	* \param arg user argument pointing to a drm_ctx_priv_map structure.
	171	* \return zero on success or a negative number on failure.
	172	*
	173	* Searches the mapping specified in \p arg and update the entry in
	174	* drm_device::ctx_idr with it.
	175	*/
	176	int drm_setsareactx(struct drm_device dev, void data,
	177	struct drm_file *file_priv)
	178	{
	179	struct drm_ctx_priv_map *request = data;
	180	struct drm_local_map *map = NULL;
	181	struct drm_map_list *r_list = NULL;
	182
	183	mutex_lock(&dev->struct_mutex);
	184	list_for_each_entry(r_list, &dev->maplist, head) {
	185	if (r_list->map
	186	&& r_list->user_token == (unsigned long) request->handle)
	187	goto found;
	188	}
	189	bad:
	190	mutex_unlock(&dev->struct_mutex);
	191	return -EINVAL;
	192
	193	found:
	194	map = r_list->map;
	195	if (!map)
	196	goto bad;
	197
	198	if (IS_ERR(idr_replace(&dev->ctx_idr, map, request->ctx_id)))
	199	goto bad;
	200
	201	mutex_unlock(&dev->struct_mutex);
	202
	203	return 0;
	204	}
	205
	206	/@}/
	207
	208	/******************************************************************/
	209	/** \name The actual DRM context handling routines */
	210	/@{/
	211
	212	/**
	213	* Switch context.
	214	*
	215	* \param dev DRM device.
	216	* \param old old context handle.
	217	* \param new new context handle.
	218	* \return zero on success or a negative number on failure.
	219	*
	220	* Attempt to set drm_device::context_flag.
	221	*/
	222	static int drm_context_switch(struct drm_device * dev, int old, int new)
	223	{
	224	if (test_and_set_bit(0, &dev->context_flag)) {
	225	DRM_ERROR("Reentering -- FIXME\n");
	226	return -EBUSY;
	227	}
	228
	229	DRM_DEBUG("Context switch from %d to %d\n", old, new);
	230
	231	if (new == dev->last_context) {
	232	clear_bit(0, &dev->context_flag);
	233	return 0;
	234	}
	235
	236	return 0;
	237	}
	238
	239	/**
	240	* Complete context switch.
	241	*
	242	* \param dev DRM device.
	243	* \param new new context handle.
	244	* \return zero on success or a negative number on failure.
	245	*
	246	* Updates drm_device::last_context and drm_device::last_switch. Verifies the
	247	* hardware lock is held, clears the drm_device::context_flag and wakes up
	248	* drm_device::context_wait.
	249	*/
	250	static int drm_context_switch_complete(struct drm_device *dev,
	251	struct drm_file *file_priv, int new)
	252	{
	253	dev->last_context = new; /* PRE/POST: This is the _only_ writer. */
	254
	255	if (!_DRM_LOCK_IS_HELD(file_priv->master->lock.hw_lock->lock)) {
	256	DRM_ERROR("Lock isn't held after context switch\n");
	257	}
	258
	259	/* If a context switch is ever initiated
	260	when the kernel holds the lock, release
	261	that lock here. */
	262	clear_bit(0, &dev->context_flag);
	263
	264	return 0;
	265	}
	266
	267	/**
	268	* Reserve contexts.
	269	*
	270	* \param inode device inode.
	271	* \param file_priv DRM file private.
	272	* \param cmd command.
	273	* \param arg user argument pointing to a drm_ctx_res structure.
	274	* \return zero on success or a negative number on failure.
	275	*/
	276	int drm_resctx(struct drm_device dev, void data,
	277	struct drm_file *file_priv)
	278	{
	279	struct drm_ctx_res *res = data;
	280	struct drm_ctx ctx;
	281	int i;
	282
	283	if (res->count >= DRM_RESERVED_CONTEXTS) {
	284	memset(&ctx, 0, sizeof(ctx));
	285	for (i = 0; i < DRM_RESERVED_CONTEXTS; i++) {
	286	ctx.handle = i;
	287	if (copy_to_user(&res->contexts[i], &ctx, sizeof(ctx)))
	288	return -EFAULT;
	289	}
	290	}
	291	res->count = DRM_RESERVED_CONTEXTS;
	292
	293	return 0;
	294	}
	295
	296	/**
	297	* Add context.
	298	*
	299	* \param inode device inode.
	300	* \param file_priv DRM file private.
	301	* \param cmd command.
	302	* \param arg user argument pointing to a drm_ctx structure.
	303	* \return zero on success or a negative number on failure.
	304	*
	305	* Get a new handle for the context and copy to userspace.
	306	*/
	307	int drm_addctx(struct drm_device dev, void data,
	308	struct drm_file *file_priv)
	309	{
	310	struct drm_ctx_list *ctx_entry;
	311	struct drm_ctx *ctx = data;
	312
	313	ctx->handle = drm_ctxbitmap_next(dev);
	314	if (ctx->handle == DRM_KERNEL_CONTEXT) {
	315	/* Skip kernel's context and get a new one. */
	316	ctx->handle = drm_ctxbitmap_next(dev);
	317	}
	318	DRM_DEBUG("%d\n", ctx->handle);
	319	if (ctx->handle == -1) {
	320	DRM_DEBUG("Not enough free contexts.\n");
	321	/* Should this return -EBUSY instead? */
	322	return -ENOMEM;
	323	}
	324
	325	ctx_entry = kmalloc(sizeof(*ctx_entry), GFP_KERNEL);
	326	if (!ctx_entry) {
	327	DRM_DEBUG("out of memory\n");
	328	return -ENOMEM;
	329	}
	330
	331	INIT_LIST_HEAD(&ctx_entry->head);
	332	ctx_entry->handle = ctx->handle;
	333	ctx_entry->tag = file_priv;
	334
	335	mutex_lock(&dev->ctxlist_mutex);
	336	list_add(&ctx_entry->head, &dev->ctxlist);
	337	mutex_unlock(&dev->ctxlist_mutex);
	338
	339	return 0;
	340	}
	341
	342	/**
	343	* Get context.
	344	*
	345	* \param inode device inode.
	346	* \param file_priv DRM file private.
	347	* \param cmd command.
	348	* \param arg user argument pointing to a drm_ctx structure.
	349	* \return zero on success or a negative number on failure.
	350	*/
	351	int drm_getctx(struct drm_device dev, void data, struct drm_file *file_priv)
	352	{
	353	struct drm_ctx *ctx = data;
	354
	355	/* This is 0, because we don't handle any context flags */
	356	ctx->flags = 0;
	357
	358	return 0;
	359	}
	360
	361	/**
	362	* Switch context.
	363	*
	364	* \param inode device inode.
	365	* \param file_priv DRM file private.
	366	* \param cmd command.
	367	* \param arg user argument pointing to a drm_ctx structure.
	368	* \return zero on success or a negative number on failure.
	369	*
	370	* Calls context_switch().
	371	*/
	372	int drm_switchctx(struct drm_device dev, void data,
	373	struct drm_file *file_priv)
	374	{
	375	struct drm_ctx *ctx = data;
	376
	377	DRM_DEBUG("%d\n", ctx->handle);
	378	return drm_context_switch(dev, dev->last_context, ctx->handle);
	379	}
	380
	381	/**
	382	* New context.
	383	*
	384	* \param inode device inode.
	385	* \param file_priv DRM file private.
	386	* \param cmd command.
	387	* \param arg user argument pointing to a drm_ctx structure.
	388	* \return zero on success or a negative number on failure.
	389	*
	390	* Calls context_switch_complete().
	391	*/
	392	int drm_newctx(struct drm_device dev, void data,
	393	struct drm_file *file_priv)
	394	{
	395	struct drm_ctx *ctx = data;
	396
	397	DRM_DEBUG("%d\n", ctx->handle);
	398	drm_context_switch_complete(dev, file_priv, ctx->handle);
	399
	400	return 0;
	401	}
	402
	403	/**
	404	* Remove context.
	405	*
	406	* \param inode device inode.
	407	* \param file_priv DRM file private.
	408	* \param cmd command.
	409	* \param arg user argument pointing to a drm_ctx structure.
	410	* \return zero on success or a negative number on failure.
	411	*
	412	* If not the special kernel context, calls ctxbitmap_free() to free the specified context.
	413	*/
	414	int drm_rmctx(struct drm_device dev, void data,
	415	struct drm_file *file_priv)
	416	{
	417	struct drm_ctx *ctx = data;
	418
	419	DRM_DEBUG("%d\n", ctx->handle);
	420	if (ctx->handle != DRM_KERNEL_CONTEXT) {
	421	if (dev->driver->context_dtor)
	422	dev->driver->context_dtor(dev, ctx->handle);
	423	drm_ctxbitmap_free(dev, ctx->handle);
	424	}
	425
	426	mutex_lock(&dev->ctxlist_mutex);
	427	if (!list_empty(&dev->ctxlist)) {
	428	struct drm_ctx_list pos, n;
	429
	430	list_for_each_entry_safe(pos, n, &dev->ctxlist, head) {
	431	if (pos->handle == ctx->handle) {
	432	list_del(&pos->head);
	433	kfree(pos);
	434	}
	435	}
	436	}
	437	mutex_unlock(&dev->ctxlist_mutex);
	438
	439	return 0;
	440	}
	441
	442	/@}/